Not all methylcobalamin is the same, there are huge differences in potency and it's not about the mg's. This is the best B12 I've tried. Most sublingual methylcobalamin has no noticeable effect on me. (No B12 alleviates my tiredness, but good B12 products make me sleep deeper.) This works better for me than some 10 mg products. Combined with some adenosylcobalamin the effect is very noticeable. Just don't chew it, but place it under your tongue or lip for maximal absorption.

Very effective, and long lasting. These do not melt in the mouth as quickly as the Jarrow methyl-B12 tablets, so I think I can absorb more of the methylcobalamin. Too bad each tablet only has 1mg of B12!

I definitely notice an energy increase on this. I have moderate ME/CFIDS. I take this with Solgar metafolin throughout the day, sublingually.
Also, make sure you have potassium supplements on hand when you take this, to avoid getting leg cramps from low potassium. I was salt loading for orthostatic intolerance before taking this, now I am potassium loading and using only a normal amount of salt. This is a huge difference for me.

Effective form of B12 that tastes great and is fast-dissolving. I chew them and let the product diffuse through the membranes of the mouth, which only takes a minute or so. I take B12 early in the day, which tends to have an energising effect.
This product is invaluable if you are an under-methylator in which case you may feel fatigued, irritable, susceptible to hayfever, have elevated homocysteine and suffer from sleep problems. You might also benefit from taking extra methionine, however I would not suggest supplementing methionine in the absence of B12 plus a B-complex because B vitamins are essential in driving the methylation cycle and lowering toxic homocysteine levels.